You are approaching it from the wrong side. You don't have to create identity and principal manually, assuming you are not creating a custom authentication module.
In any other case, you only choose the persistence mechanism and the corresponding authentication module sets the identity/principal according to the persistence.
A commonly used persistence mechanism is Forms Authentication, where you issue forms cookies. The forms authentication module makes sure the identity/principal is set early in the pipeline and takes the cookie as the source of information.
If you want to replace the cookie by your custom cookie (in other words - replace forms authentication with your own) - you have to think of a way to persist the security info, to the cookie for example.
Note, however, that this is probably not necessary. The very same forms authentication can be used with any custom membership and role providers. This is because these two have different responsibilities - membersip provider is for actual authentication whereas forms authentication module is for persisting the information for consecutive requests.
Edit: to add a role for a user so that it is persisted in the user database:
Roles.AddUsersToRoles( ... );
But first, you'd have to create users in the user database:
Membership.CreateUser( ... );
Note that Roles
and Membership
are facades for actual role and membership providers. While default providers use the membership database, you can easily create custom providers that persist the information anywhere at the server side.